Trachemys dorbigni, the Brazilian slider turtle, occurs in the southernmost portion of South America in Brazil, Uruguay, and Argentina. Despite being an abundant species in southern Brazil, its helminth fauna is little known. In this context, 60 turtles from southern Brazil were examined for helminths. The nematodes Spiroxys contortus (Gnathostomatidae) and Falcaustra affinis (Kathlaniidae) were found, both representing new host records. This is the southernmost locality reported for Falcaustra affinis, as the previous known extent of its southern distribution was in Mexico.